1) Keep SW off the big screen after Jedi. Sure, this option keeps huge dollars out of his coffers. Still, he was never going to leave this earth anywhere close to poor. There's still residuals from merchandise and EU novels. My guess is that if there were no SE or PT in the works, the EU explosion would not have been what it became.
2) Let somebody else write and direct the PT. Obviously, GL was too close to SW to let that happen - it gave him everything one could ever get - but perhaps he should have thought it through a bit more: If the new PT was crap, it's not his fault. If the new PT was good, that crew is simply standing on GL's shoulders. Either way, GL would have made a killing without personally butchering the product, as it happened in real life.
I guess what I mean by all of this babbling is to say that SW was at it best when so much was left to the imagination. Until recently, we didn't know who Luke's mother was, what the Clone Wars were, how the Empire came to be, what the person behind the Boba Fett mask looked like, and so on. GL shoehorning a bunch of explanations for every unfilled gap in the OT just made the SW universe poorer. Legends should always be left alone.